Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. James Benjamin Grossweiner, M.D.

Dermatology Physician in Naperville, IL · enumerated 2006 · practices at Grossweiner & Blaszak, P.C..

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1437114907

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Registry record

Entity type Individual (Type 1)

Name Dr. James Benjamin Grossweiner

Credential M.D.

Sex Male

Practice address 1220 Hobson Rd Ste 116, Naperville, IL, 60540

Phone (630) 355-6660

Fax (630) 527-2856

Enumeration date Apr 19, 2006

Last updated in NPPES Jul 18, 2022

Taxonomy & licenses

207N00000X Dermatology Physician Allopathic & Osteopathic Physicians · License 036-074040 (IL) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
2201677	Other	IL	BCBS
070011565	Other	IL	MEDICARE R.R.
036074040	Medicaid	IL	-
0300111	Other	IL	UHC

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

Is NPI 1437114907 active?

Yes, as of the latest NPPES snapshot, NPI 1437114907 is active (record last updated 2022-07-18).

How do I verify James Grossweiner's NPI record?

Cross-check NPI 1437114907 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Other providers at this practice address

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Wayne Blaszak Dermatology Physician · Naperville, IL NPI 1245294008 Grossweiner & Blaszak, P.C. Dermatology Physician · Naperville, IL NPI 1194789990

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2022-07-18.